链接：https://blog.csdn.net/u013894427/article/details/83827173
pthread 入口函数类型说明void * func1(void * t)void* 表示无类型指针
void*作为函数参数，表示函数接收一个指针，不管是什么类型的指针都可以，但是传递之前要强制转换为无类型指针。
基础流程pthread_t t1;//声明一个线程pthread_create(&t1, NULL, &test, (void *)this);//创建一个线程pthread_exit(NULL);//退出线程
pthread_create()
函数原型
int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine) (void *), void *arg);含有四个参数，
第一个参数表示线程id第二个参数表示线程参数第三个是线程的入口函数名字第四个参数表示线程入口函数的参数名字
pthread_exit();
函数原型
void pthread_exit（void *retval）
写在线程内部，用于强制退出当前线程
如果线程是joinable，可以在函数参数里面传递线程的退出信息给主线程
例如
#include <pthread.h>#include <iostream>
using namespace std;
void *thread1(void *);int status;int main(void){ void *status_m; cout << "status_m addr is " << &status_m << endl; pthread_t t_a; pthread_create(&t_a,NULL,thread1,NULL);/*创建进程t_a*/ pthread_join(t_a, &status_m);/*等待进程t_a结束*/ cout << "status_m value is " << status_m << endl; int * re=(int *)status_m; cout << "the value is " << *re << endl; return 0;}void *thread1(void *junk){ status=23333; cout << "status addr is " << &status << endl; pthread_exit((void *)&status);}
可以打印出
status_m addr is 0x7ffe3cfd6170status addr is 0x6021b4status_m value is 0x6021b4the value is 23333线程的joinable和detached属性属性的设置方法如下
pthread_attr_t attr;//声明一个参数pthread_attr_init(&attr);//对参数进行初始化pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);//设置线程为可连接的pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);//设置线程为可分离的pthread_attr_destroy(&attr)//销毁属性，防止内存泄漏属性的相关操作如下：
pthread_detach()
函数原型
int pthread_detach(pthread_t tid);1detached的线程在结束的时候会自动释放线程所占用的资源
pthread_join()
函数原型
int pthread_join(pthread_t tid, void **status);joinable的线程必须用pthread_join()函数来释放线程所占用的资源，如果没有执行这个函数，那么线程的资源永远得不到释放。
互斥锁 mutex互斥锁是为了多个线程在运行过程中保持数据同步引入的机制。
基本流程
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;/*初始化互斥锁*/pthread_mutex_init(&mutex,NULL);/*动态初始化互斥锁*/pthread_mutex_lock(&mutex);//加锁pthread_mutex_unlock(&mutex);//解锁pthread_mutex_destroy(&mutex);//销毁互斥锁举个例子
#include <pthread.h>#include <stdio.h>#include <unistd.h>
pthread_mutex_t mutex ;void *print_msg(void *arg){ int i=0; pthread_mutex_lock(&mutex); for(i=0;i<15;i++){ printf("output : %d\n",i); usleep(100); } pthread_mutex_unlock(&mutex);}int main(int argc,char** argv){ pthread_t id1; pthread_t id2; pthread_mutex_init(&mutex,NULL); pthread_create(&id1,NULL,print_msg,NULL); pthread_create(&id2,NULL,print_msg,NULL); pthread_join(id1,NULL); pthread_join(id2,NULL); pthread_mutex_destroy(&mutex); return 1;}条件变量基本流程
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;/*初始化互斥锁*/pthread_cond_t cond = PTHREAD_COND_INITIALIZER;/*初始化条件变量*/pthread_mutex_lock(&mutex);/*锁住互斥量*/pthread_cond_signal(&cond);//发送信号量 跟wait函数不在同一个线程中pthread_cond_wait(&cond,&mutex);//阻塞线程，等待条件变量，同时解锁互斥量pthread_mutex_unlock(&mutex);//解锁互斥量pthread_mutex_destroy(&mutex);//销毁互斥锁pthread_cond_destroy(&cond);//销毁条件变量举个例子
#include <pthread.h>#include <stdio.h>#include <stdlib.h>#include <unistd.h>pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;/*初始化互斥锁*/pthread_cond_t cond = PTHREAD_COND_INITIALIZER;/*初始化条件变量*/
void *thread1(void *);void *thread2(void *);
int i=1;
int main(void){ pthread_t t_a; pthread_t t_b; pthread_create(&t_a,NULL,thread1,(void *)NULL);/*创建进程t_a*/ pthread_create(&t_b,NULL,thread2,(void *)NULL); /*创建进程t_b*/ pthread_join(t_a, NULL);/*等待进程t_a结束*/ pthread_join(t_b, NULL);/*等待进程t_b结束*/ pthread_mutex_destroy(&mutex); pthread_cond_destroy(&cond); exit(0);}void *thread1(void *junk){ for(i=1;i<=6;i++) { printf("thread1: Line: %d, i = %d\n", __LINE__, i); pthread_mutex_lock(&mutex);/*锁住互斥量*/ printf("thread1: lock %d\n", __LINE__); if(i%3==0) { printf("thread1:signal 1 %d\n", __LINE__); pthread_cond_signal(&cond);/*条件改变，发送信号，通知t_b进程*/ printf("thread1:signal 2 %d\n", __LINE__); printf("%s will sleep 1s in Line: %d \n", __FUNCTION__, __LINE__); sleep(1); } pthread_mutex_unlock(&mutex);/*解锁互斥量*/ printf("thread1: unlock %d\n", __LINE__); printf("%s will sleep 1s in Line: %d \n\n", __FUNCTION__, __LINE__); sleep(1); }}
void *thread2(void *junk){ while(i<6) { printf("thread2: Line: %d, i = %d\n", __LINE__, i); pthread_mutex_lock(&mutex); printf("thread2: lock %d\n", __LINE__); if(i%3!=0) { printf("thread2: wait 1 %d\n", __LINE__); pthread_cond_wait(&cond,&mutex);/*解锁mutex，并等待cond改变*/ printf("thread2: wait 2 %d\n", __LINE__); } pthread_mutex_unlock(&mutex); printf("thread2: unlock %d\n", __LINE__); printf("%s will sleep 1s in Line: %d \n\n", __FUNCTION__, __LINE__); sleep(1); }}结果为：
thread1: Line: 29, i = 1thread1: lock 31thread1: unlock 41thread1 will sleep 1s in Line: 42
thread2: Line: 52, i = 1thread2: lock 54thread2: wait 1 57thread1: Line: 29, i = 2thread1: lock 31thread1: unlock 41thread1 will sleep 1s in Line: 42
thread1: Line: 29, i = 3thread1: lock 31thread1:signal 1 34thread1:signal 2 36thread1 will sleep 1s in Line: 37 thread1: unlock 41thread1 will sleep 1s in Line: 42
thread2: wait 2 59thread2: unlock 62thread2 will sleep 1s in Line: 63
thread1: Line: 29, i = 4thread1: lock 31thread1: unlock 41thread1 will sleep 1s in Line: 42
thread2: Line: 52, i = 4thread2: lock 54thread2: wait 1 57thread1: Line: 29, i = 5thread1: lock 31thread1: unlock 41thread1 will sleep 1s in Line: 42
thread1: Line: 29, i = 6thread1: lock 31thread1:signal 1 34thread1:signal 2 36thread1 will sleep 1s in Line: 37 thread1: unlock 41thread2: wait 2 59thread2: unlock 62thread2 will sleep 1s in Line: 63
thread1 will sleep 1s in Line: 42 注意:thread2 wait 1和thread2 wait 2的位置可以知道wait函数在执行的时候会阻塞thread2,并且解锁互斥量
转载于:https://www.cnblogs.com/lyggqm/p/11451855.html
相关资源：Pthread 多线程C 动态库 静态库 头文件